The author's concept of the distance and tracking control problem for autonomous vehicles relates to the cooperative behaviour of two successive vehicles travelling in the same environment. This behaviour requires one vehicle, designated the leader to move autonomously around it's environment with other vehicles, designated followers maintaining a coincident travel path and desired longitudinal distance with respect to the leader. Distance and tracking control is beneficial in numerous applications including guiding autonomous vehicles in Intelligent Transport Systems (ITS) which increases traffic safety and the capacity of pre-existing road infrastructure. Service robotics may also benefit from the cost savings and flexibility offered by distance and tracking control which enables a number of robots to cooperate together in order to achieve a task beyond the capabilities ofjust one robot. Using a distance and tracking control scheme an intelligent leader robot may guide a number of less intelligent (and therefore less costly and less complex) followers to a work-site to perform a task. The author's approach to the distance and tracking control problem consisted of two separate solutions - an initial solution used as a starting point and learning experience and a second, more robust, fuzzy control-based solution. This thesis briefly describes the initial solution, but places a greater emphasis on the second solution. The reason for this is that the fuzzy control-based solution offers significant improvement on the initial solution and was developed based on conclusions drawn from the initial solution. Most implementations of distance and tracking control, sometimes referred to as Intelligent Cruise Control (ICC) or platooning, are limited to longitudinal distance control only. The leader tracking control is performed either implicitly by a separate lane-following control system or by human drivers. The fuzzy control-based solution offered in this thesis performs both distance and tracking control of an autonomous follower vehicle with respect to a leader vehicle in front of it. It represents a simple and cost effective solution to the requirements of autonomous vehicles operating in ITS schemes - particularly close formation platooning. The follower tracks a laser signal emitted by the leader and monitors the distance to the follower at the same time using ultrasonic ranging techniques. The follower uses the data obtained from these measuring techniques as inputs to a fuzzy controller algorithm to adjust its distance and alignment with respect to the leader. Other systems employed on road vehicles utilise video-based leader tracking, or a range of lane-following methods such as magnetometer or video-based methods. Typically these methods are disadvantaged by substantial unit and/or infrastructure costs associated with their deployment. The limitations associated with the solutions presented in this thesis arise in curved trajectories at larger longitudinal distance separations between vehicles. The effects of these limitations on road vehicles has yet to be fully quantified, however it is thought that these effects would not disadvantage its use in close formation platooning. The fuzzy control-based distance and tracking control solution features two inputs, which are the distance and alignment of the follower with respect to the leader. The fuzzy controller asserts two outputs, which are left and right wheel velocities to control the speed and trajectory of a differential drive vehicle. Each of the input and output fuzzy membership functions has seven terms based around lambda, Z-type and S-type functions. The fuzzy rule base consists of 49 rules and the fuzzy inference stage is based on the MAX/MIN method. A Centre of Maximum (CoM) def'uzzification method is used to provide the two crisp valued outputs to the vehicle motion control. The methods chosen for the fuzzy control of distance and tracking for autonomous vehicles were selected based on a compromise between their computational complexity and performance characteristics. This compromise was necessary in order to implement the chosen controller structure on pre-existing hardware test beds based on an 8-bit microcontrollers with limited memory and processing resources. Overall the fuzzy control-based solution presented in this thesis effectively solves the distance and tracking control problem. The solution was applied to differential drive hardware test-beds and was tested to verify performance. The solution was thoroughly tested in both the simulation environment and on hardware test-beds. Several issues are identified in this thesis regarding the application of the solution to other platforms and road vehicle use. The solution will be shown to be directly portable to service robotics applications and, with minor modifications, applicable to road vehicle close-formation platooning.

<p>When a helicopter is flying, the dynamics vary depending on, for example, speed and position. Hence, a time-invariant linear model cannot describe its properties under all flight conditions. It is therefore desirable to update the linear helicopter model continuously during the flight. In this thesis, two different recursive estimation methods are presented, LMS (Least Mean Square) and adaptation with a Kalman filter. The main purpose of the system estimation is to get a model which can be used for feedback control. In this report, the estimated model will be used to create a LQ controller with the task of keeping the output signal as close to the reference signal as possible.Simulations in this report show that adaptive feedback control can be used to control a helicopter's angular velocities and that the possibility to use an adaptive control algorithm in a real future helicopter is good.</p>

<p><p>This paper is the result of a master thesis project on helicopter rotor downwash effects using computational fluid dynamics (CFD). The work was performed at the department of Aerodynamics and Flight Mechanics at Saab AB, Linköping in 2008. It completes the author’s studies for a M.Sc degree in Applied Physics and Electrical Engineering at the Department of Electrical Engineering at the Linköping institute of technology (LiTH), Linköping, Sweden.</p><p> </p><p>The aim of the project was to study the rotor downwash effects and its influence on the helicopter fuselage. To fulfil this purpose, several CFD calculations were carried out and the aerodynamic forces and moments resulting from the calculations were implemented in an existing simulation model, developed in-house at Saab. The original (existing) model was compared to the updated model by studying step responses in MATLAB, Simulink. For some step commands, the comparisions indicated that the updated model was more damped in yaw compared to the original model for the hovering helicopter. When the helicopter was trimmed for a steady turn, the states in the updated model diverged much faster than the states in the original model for any given step command.</p><p> </p><p> </p><p>In order to investigate the differences between the original helicopter model and the updated model from a controlling perspective, a linear quadratic (LQ) state feedback controller was synthesized to stabilize the vehicle in a steady turn. The LQ method was chosen as it is a modern design technique with good robustness and sensitivity properties and since it is easily implemented in MATLAB.  Before synthesising, a simplification of the helicopter model was made by reducing states and splitting them into lateral and longitudinal ones. Step responses from simulations with the original and the updated model were studied, showing an almost identical behavior.</p><p> </p><p>It can be concluded that the aerodynamic coefficients obtained from the CFD calculations can be used for determining the aerodynamic characteristics of the helicopter. Some further validation is needed though, for example by comparing the results with flight test data. In order to build an aerodynamic data base that covers the whole flight envelop, additional CFD calculations are required.</p><p> </p></p>

<p>This thesis was done at DaimlerChrysler AG in Stuttgart,Germany. The aim of the thesis is to develop an algorithm for controlling a motor used in a Shift-by-Wire System. The control algorithm is to be implemented in a prototype car for further testing. The Shift-by-Wire System can be described as follows: An electrical actuator is mounted in an automatic gearbox to select gears instead of the gear stick. The actuator is controlled by a microcontroller, which runs a control algorithm. The position of the actuator is measured with a linear position sensor and sent to the controller.</p>

<p>This thesis presents the theory behind prototyping and user interviews as parts of requirements analysis. It further discusses how these were used in the development of a budget planning application. </p><p>The implemented Web-based solution uses a new component-based design rooted in a Model-View-Controller architecture. The application is used today with complete success at the Department of Computer and Information Science at Linköping University.</p>

<p>Automation in manufacturing has come far by using industrial robots. However, industrial robots require tremendous efforts in static calibration due to their lack of senses. Force and vision are the most useful sensing capabilities for a robot system operating in an unknown or uncalibrated environment [4]and by integrating sensors in real-time with industrial robot controllers, dynamic processes need far less calibration which leads to reduced lead time. By using robot systems which are more dynamic and can perform complex tasks with simple instructions, the production efficiency will rise and hence also the profit for companies using them. </p><p>Although much research has been presented within the research community, current industrial robot systems have very limited support for external sensor feedback, and the state-of-the-art robots today have generally no feedback loop that can handle external force- or position controlled feedback. Where it exists, feedback at the rate of 10 Hz is considered to berare and is far from real-time control. </p><p>A new system where the feedback control can be possible within a real-time behavior, developed at Lund Institute of Technology, has been implemented and deployed at Linköping Institute of Technology. </p><p>The new system for rapid feedback control is a highly complex system, possible to install in existing robot cells, and enables real-time (250 Hz) sensor feedback to the robot controller. However, the system is not yet fully developed, and a lot of issues need to be considered before it can reach the market in other than specific applications. </p><p>The implementation and deployment of the new interface at LiTH shows that the potential for this system is large, since it makes production with robots exceedingly flexible and dynamic, and the fact that the system works with real- time feedback makes industrial robots more useful in tasks for manufacturing.</p>

<p>This master thesis is a result of the work carried out for Research Electronics at Siljansnäs. The company develops customized electronical systems. Because of the rapidly increasing interest in colour displays there has been a desire within the company to represent information from sensors and electrical systems in a more advanced way.</p><p>Due to the mentioned reason above we were given the assignment to solve how a colour display using the STN technique works. The technique is used by small displays, the size of QVGA. Our ambition of this diploma work is to develop a fully functionally test prototype to evaluate the LCD (Liquid Crystal Display) and the LCD controller. The most important results from this study is the documentation of how a LCD controller works and how the pixels are addressed. We succeded in showing all the pixels we were able to address at the right place on the LCD wich indicates that there is a compatibility between the LCD and the LCD controller . A replacement of the LCD is recommended because of the difficulties working with it. Precisely wich LCD it should be replaced with is not mentioned in this report because of the extent of the work. One of the aims was to evaluate the function of the LCD, not to find an alternative LCD.When studiyng the LPC2129 and MC68K it emerged that both suits well as controlling units for this application, but an implemention with LPC2129 involves greater diffculties because of the absence of external system bus. Our aim is that this work will function as a starting point to further development leading to a controlling unit in working order, and that it will be implemented in other products the company develops.</p> / <p>Föreliggande rapport behandlar vårt magisterarbete på 20 poäng. Arbetet är gjort åt Research</p><p>Electronics i Siljansnäs som utvecklar skräddarsydda elektroniksystem. På grund av den ökade efterfrågan av färgdisplayer från marknaden har det länge funnits ett behov av att presentera information från givare och mätinstrument på ett mer avancerat sätt.</p><p>Av ovan nämnda skäl fick vi i uppdrag att undersöka hur en färgdisplay av typen STN (Super Twist Nematic) fungerar. Det är oftast små displayer som använder den här tekniken. Målet från början var att utveckla en fungerande testprototyp för att testa grafikcontrollern och displayen. De viktigaste resultat som framkommit efter arbetet är en dokumentation på hur en grafikcontroller fungerar och hur adressering av pixlar sker. Vi har visat att det är möjligt att använda den givna grafikcontrollern tillsammans med den display som köpts in då alla pixlar som gick att adressera visats på önskad plats på skärmen. Det finns också en rekommendation av byte till en annan display som är enklare att arbeta med. Exakt vilken anges inte i rapporten eftersom det inte har ingått i arbetet att ta hitta en alternativ display utan att undersöka den befintliga. Studien av mikrocontrollern LPC2129 från Philips och processorn MC68K från Freescale visar att båda är bra för applikationen. LPC2129 blir svårare att arbeta med till följd av att det saknas extern systembuss. Våra förhoppningar är att examensarbetet ska bli en god grund för fortsatt arbete som leder till en färdig produkt, och att den används i övriga tillämpningar i företaget.</p>

<p>The longitudinal controller at DaimlerChrysler AG consists of two cascade controllers. The outer control loop contains the driver assistance functions such as speed limiter, cruise control, etc. The inner control loop consists of a PID-controller and an observer. The task of the observer is to estimate the part of the vehicle's acceleration caused by large disturbances, for example by a changed vehicle mass or the slope of the road.</p><p>As observer the Kalman filter is selected. It is the optimal filter when the process model is linear and the process noise and measurement noise can be modeled as Gaussian noise. In this Master's thesis the theory for the Kalman filter is presented and it is shown how to choose the filter parameters. Simulated annealing is a global optimization technique which can be used when autotuning, i.e., automatically find the optimal parameter settings. To be able to perform autotuning for the longitudinal controller one has to model the environment and driving situations.</p><p>In this Master's thesis it is verified that the parameter choice is a compromise between a fast but jerky, or a slow but smooth estimate. As the output from the Kalman filter is directly added to the control value for the engine and brakes, it is important that the output is smooth. It is shown that the Kalman filter implemented in the test vehicles today can be exchanged with a first-order lag function, without loss in performance. This makes the filter tuning easier, as there is only one parameter to choose.</p><p>Change detection is a method that can be used to detect large changes in the signal, and react accordingly - for example by making the filter faster. A filter using change detection is implemented and simulations show that it is possible to improve the estimate using this method. It is suggested to implement the change detection algorithm in a test vehicle and evaluate it further.</p>

<p>Much functionality of today's vehicles runs as software on embedded computer systems. This includes, for example, automatic climate control and engine control.</p><p>As the processors necessarily are located in diffent physical locations inside the vehicle wires must be drawn between processors that need to communicate. Therefore, it is typical to have one or several buses connecting the processors in an embedded computer network, thus creating a distributed system. As some parts of the system in the car have real-time properties, it is necessary to validate that the real-time properties are upheld in the distributed system.</p><p>This thesis presents the design and implementation of an adaptive cruise controller (ACC), which is a cruise controller that also keeps a minimum distance to the closest vehicle in front. Further, the performance of the ACC has been evaluated using an existing system-level simulator for distributed real-time systems together with metrics for Quality-of-Control (QoC).</p><p>The ACC has then been simulated under different scenarios. The scenarios include outside conditions, for example the slope of the road, the behaviour of the vehicle in front, and the desired velocity, as well as internal conditions as adding different amounts of extra load on the processors and the bus.</p><p>The results show that the functionality of the ACC starts deteriorating when the extra load on the nodes reaches high levels. When the extra load reaches very high levels, the ACC stops functioning completely. The results also show that the extra load on the bus has very little effect on the performance of the ACC.</p>

<p>The PhonePages of Sweden is a company that develops software for mobile units, especially cell phones. This thesis treats the development of, and contingencies for, a mobile phone directory, using the limited resources found in a mobile unit. The project was implemented and executed at The PhonePages with the intention of creating a product to sell to a third party.</p><p>By studying different solutions, their benefits and drawbacks, an abstract picture of the product was constructed. Problems covered include compatibility problems caused by todays platform diversity as well as problems with saving, organizing and presenting data.</p><p>The main goal was to create a phone directory which does not make external information retrievals. The service should contain both company and personal information, with name and phonenumber. Complete address information should also be available. The application should also manage different priorities and logotypes for the company information. The application, that emerged as a result of our work at The PhonePages, works independently, without making connections to the Internet and is completely implemented in J2ME, all according to the requirement specification. In other words, the analysis of the different solutions led to a working application.</p>